optional keywords and parameters are referred to as
options or are enclosed in square brackets: [ ]

mutually exclusive choices are separated by a vertical bar: |

mutually exclusive choices of a required item are grouped with
parentheses: ( )

The brackets, vertical bars, and parentheses mentioned above are
merely symbolic and should not be included in the typed command.

All commands can be truncated to unique strings. Keyword truncation is not
allowed unless a command's manual page states otherwise.

Multiple commands can be combined on a single line, separated by semicolons.
This may be useful because the display
is not redrawn until the last command in a semicolon-separated series
has been executed; that is, multiple graphical changes such as changes in
representation, color, and display state can be made to appear
simultaneously instead of one by one.